so I am a new chicken momma.I got a batch of six bantams from TSC about 3 weeks ago. They have been doing great. Today I went to bowman's to get some feedand they had a new batch of cuckoo Marans only a few days old. the girl told me that they should do fine with my bantams. so here is my question... I had been feeding my older chicks regular baby chick food. The girl at bowmans told me that I should have all of the chicks on medicated food until 16 to 18 weeks. She told me to switch them over. So I bought the bag of medicated food and came home and put everyone on it. this evening I have found a few bloody stools from the older chickens. I am worried that this could be the cocci bacteria I hear about or is it from switching the food?! I keep the pen that they are in really clean! And I clean their water every single day! Usually 2 to 3 times a day. I plan on going in the morning and getting medicine to treat them all. But I am really upset. Thoughts??